Regular casting methods such as conventional die casting, gravity permanent mold casting, and squeeze casting have long been used for metals and their alloys. However, these current processes when used to manufacture parts with relatively complex geometries often yield products with undesirable shrink porosity, which can adversely impact the quality and integrity of the part. Shrink porosity defines a condition that arises as a metal part begins to shrink as it cools and solidifies along the outer surface, leaving “voids” trapped in the center of the part. If the voids are not reconstituted with metal, the cast part is termed “porous.” Particularly in the design of complex parts, such as, for example, automotive steering knuckles, the greatest shrink porosity is found in the thicker areas. Furthermore, this condition is especially prevalent in conjunction with the use of Aluminum alloys.
Accordingly, it is desirable to provide a method of casting metals and alloys utilizing conventional and/or rheocasting die casting devices that can impart desirable mechanical properties. It is further desirable to provide a process to control the shrink porosity of cast parts at multiple locations though out a part.